Growth of Boron Nitride Nanotubes Having Large Surface Area Using Mechanothermal Process

Abstract

Nanostructures of boron nitride (BN) including nanotubes, nanofibers and nanosheets having a large surface area are very useful in storing hydrogen and other gases. In the present paper we report the synthesis and characterization of these nanostructures of BN using mechanothermal process. Under this process elemental boron powder is first ball milled to about 50 h in an inert atmosphere and then annealed at 1100˚C -1250˚C for 6 h in the presence of NH 3 gas. By this treatment nanotubes and other nanostructures of BN were synthesized. The diameter of BN nanotubes varied from 20 to 50 nm and most of them exhibited spindle or bamboo like morphology. Because of the large surface area, these nanotubes may be explored for a better hydrogen gas storage device as compared to the crystallized nanotubes. The main advantage of this technique is that the nanotubes can be grown in large quantity. A possible growth mechanism towards the evolution of such fascinating nano-objects of boron nitride has been discussed employing high-resolution transmission electron microscopy and photoluminescence.

Temperature-Dependent Morphology Evolution of Boron Nitride and Boron Carbonitride Nanostructures

“…The droplet is finally lifted up by the stress under the curvature, thus hollow BN cap is formed [44,[52][53][54]. The continuous diffusion of BN species along the droplet surface makes BN multisheets grow layer by layer along the (002) plane and nanotube wall will form [21,48,55,56]. When the nanotube wall grows, BN species also precipitate inside the droplet via bulk diffusion, resulting in the formation of BN compartment layer.…”